untitled 1.1.b Elasticity
mobility)
An Introduction to Cloud Computing
You will set out on your journey to the destination of earning a
Cisco Certifi ed Networking Associate in cloud computing by taking
a look at the big picture of this phenomenon called the cloud . You
will be introduced to many defi nitions and concepts that will
better enable d you to truly understand the fi ner details of cloud
computing as you progress on your certi- fi cation journey. This
book will investigate both the many generic aspects of the cloud
and the details and technology pieces of the Cisco cloud service
offerings.
How Cloud Computing Is Different from Traditional Computing
Throughout this chapter and book you will be comparing the old with
the new, in other words, the traditional data center with the new
cloud-based computing model. With cloud computing, you pay for only
what you use and do not own the equipment as is usually the case in
the traditional world of corporate data centers. Cloud computing
allows you to not have to be involved with the day-to-day needs of
patching servers, swapping out failed power supplies and disk
drives, or doing any of the other myriad of issues you have to deal
with when you own and maintain your own equipment.
The cloud allows you to scale up and down on your computing needs
very quickly and to pay for only what you use and not for any
standby capacity. You can now deploy your applications closer to
your customers no matter where they are located in the world. Also,
smaller companies can use advanced services that were usually
available only with the bud- gets of the largest corporations in
the world.
Cloud computing is also different from the corporate IT models in
that the time to spin up new services is greatly reduced. There are
no large, up-front fi nancial commitments either; you are renting
capacity instead of purchasing it.
Computing as a Utility In the distant past, each and every factory
or town that needed power would be responsible for the generation
and distribution of its own electricity. The same was also true for
many
An Introduction to Cloud Computing 3
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other services such as water, gas, and telephone services that we
take for granted today. The up-front costs, ongoing maintenance,
and general headaches of operating a power plant to run your
business is unthinkable today, but this was actually commonplace in
the past. A manufacturing company, for example, would rather not
concentrate on making the power to run its factory but would
instead rather focus on their area of expertise and purchase
electricity as needed from a utility that specializes in the
generation and distribution of electrical power. However, at one
time, that was not an option!
There was also the matter of economy of scale; it is much cheaper
per unit to generate power with a single large facility than having
many small generation plants connected to each individual factory
in every town.
The computing industry took a very different track before the
cloud. Companies that needed computing resources to effectively run
their companies would purchase their own large computer systems.
This came with a heavy up-front expense not only for the computer
systems and all of the needed peripheral equipment; they also
needed to build expensive rooms to put these machines in. Since
computers can be temperamental, the data centers needed to be
cooled and the heat emitting from the computers needed to be
removed from the data center. Computers are also rather fi nicky on
electricity, demanding a steady and stable power source and lots of
it! Then there was the staff of engineers (such as your two
authors!) who meticulously designed, installed, and maintained
these systems. There were programmers and too many axillary
products and subsystems to count! Don’t worry, we are going to talk
about a lot of these systems, but believe us, you need to have an
extensive array of support products, software, and personnel to
pull all of this off.
What happens when your business fl uctuates and you are busy during
the holiday season and not so much the rest of the year, as in the
case of a retailer? Well, you will need to engi- neer and scale the
data-processing capacity to meet the anticipated heaviest load
(with some additional capacity just in case). This, of course,
means that there is usually a whole lot of idle capacity the rest
of the year. Yes, that’s right—that very expensive compute capacity
and all the trimmings such as the staff and support equipment in
the corporate data center just sits there unused the rest of the
year, making your fi nancial staff very upset.
It only gets worse. What happens when you need to add capacity as
your company, and with it your data-processing needs, grow?
As you will learn, with the progress of technology and especially
with virtualization and automation, the computing world has evolved
greatly and can now be offered as a utility service just like
electricity, gas, and water. Sure, we had to give it the fancy name
of cloud computing , but it is the process of running applications
on a computer to support yourg business operations.
However, in the past when new capacity was required, a team of
engineers would need to determine the best approach to accomplish
the company’s goals and determine the equip- ment and software that
would be required. Then the equipment list would go out for bid, or
quotes would need to be gathered. There would be time for the
purchasing cycle to get the equipment ordered. After some time, it
would be delivered at the loading dock, and the fun would really
begin. The equipment would need to be unpackaged, racked, cabled,
and powered up, and then usually a fair amount of confi guration
would take place. Then the application teams would install the
software, and even more confi guration would be
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needed. After much testing, the application would go live, and all
would be good. However, this could take a very long time, and as
that equipment aged, a new refresh cycle would begin all over
again.
With the utility model of computing, or the cloud , there are no
long design, purchas- ing, delivery, setup, and testing cycles. You
can go online, order a compute instance, and have everything up and
running in literally minutes. Also, the fi nancial staff is very
happy as there are no capital expenditures or up-front costs. It is
just like electricity—you pay for only what you use!
The Role of Virtualization The new model of computing has largely
been made possible with the widespread deploy- ment of
virtualization technologies. While the concept of taking one piece
of computing hardware and running many virtual computers inside of
it goes back decades to the days of mainframe computers, new
virtualization software and cheap, powerful hardware has brought
virtualization to the mainstream and enabled the ability to do many
amazing things in the cloud, as you will explore throughout this
study guide.
Now, with a powerful server running on commodity silicon, you can
run hundreds of virtual machines on one piece of hardware; in the
past, a physical server would often be used for each
application.
Many other functions of data center operations have also been
virtualized such as load balancers, fi rewalls, switches, and
routers. The more that is virtualized, the more cost-effective
cloud services are becoming. Also, the management and automation
sys- tems that were developed around the virtualized data center
allow for fast implementa- tion of complete solutions from the
cloud provider. It is often as simple as logging into a cloud
dashboard using a common web browser and spinning up multiple
servers, net- work connections, storage, load balances, fi rewalls,
and, of course, applications. This level of automation enabled by
virtualization is going to be a focus of the CCNA Cloud certifi
cation.
What Cloud Computing Offers That Is New Is this the same old data
center that has been moved to the other side of the Internet, or is
this something new and completely different? Well, actually it is a
little of each. What is new is that the time to bring new
applications online has been greatly reduced as the com- puting
capacity already exists in the cloud data center and is available
as an on-demand service. You can now simply order the compute
virtual machines and associated storage and services just like you
would any utility service.
The cost models are now completely different in that the up-front
costs have largely been eliminated, and you pay as you go for only
what you are using. Also, if you require additional capacity, even
for a short amount of time, you can scale automati- cally in the
cloud and then shut down the added servers when your computing
work- load decreases.
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The Growth of Cloud Computing Because of the lower total cost of
operations and short deployment times, the growth of cloud
computing has been nothing short of phenomenal. Cloud companies
that are only a few years old are now multibillion-dollar
enterprises. The growth rates are in the double digits in this
industry and seem to be increasing every year. The business model
is just too great for almost any business to ignore.
It can be diffi cult to get accurate numbers on the size of the
cloud market because of company fi nancial reporting not breaking
out their cloud fi nancials from other business entities. Also, no
one seems to really agree on what cloud computing is in the fi rst
place.
What is clear is that the growth of cloud computing is phenomenal
and is accelerating every year as more and more companies move
their operations to the cloud. It is common to see cloud growth
estimates at 25 to 40 percent or even higher every year and
accelerating for many years into the future with revenues way north
of $100 billion per year.
Migrating to the Cloud In later chapters, you will investigate what
is going to be required to migrate your comput- ing operations from
the private data center to the cloud, as shown in Figure 1.1 .
Cloud migration may not be trivial given the nature of many custom
applications and systems that have evolved over many years or are
running on platform-specifi c hardware and operating systems.
However, as virtualization technology has exploded and you gain
more experience in the cloud, there are many tools and utilities
that can make life much simpler (well, let’s just say less
complicated) than doing migrations in the past.
F I GU R E 1.1 Migrations from the corporate data center to
the cloud
Migrate Compute Resources
Corporate Data Center Cloud Provider
You cannot simply just take an application running on your
corporate data centers and fi le transfer it to the cloud. Life is
far from being that simple. The operating systems and applications
running directly on a server, such as an e-mail server, will need
to be con- verted to the virtual world and be compatible with the
virtualization technologies used by the cloud providers.
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The process of migrating to the cloud is actually a very large
business in itself, with many professional services teams working
throughout the world every day assisting in the great migration to
the cloud.
A Look at How the CCNA Role Is Evolving In the past, the networking
professional with a Cisco Certifi ed Network Associate certifi ca-
tion could often be found in the network room or wiring closet
racking a switch or router and then confi guring the VLANs and
routing protocols required to make everything work. How is our
world changing now that another company, the cloud company, owns
the net- work and the computing systems? Should we all go look for
another gig? Don’t worry, there will plenty for all of us to
do!
As you will learn on your journey to becoming a Cisco Certifi ed
Network Associate Cloud professional, the way you do things will
certainly be changing, but there will always be a demand for your
expertise and knowledge.
The cloud engineer will still be doing confi gurations and working
in consoles; it is just that you will be doing different but
related tasks. Your work will be different than the world of IOS
commands that you might know and love, but that is a good
thing.
You will be doing higher-level work on the cloud deployments and
not be concerned with the underlying hardware and systems as much
since that will be the responsibility of the cloud service
providers. Also, the siloed world between the different groups in
the data center, such as networking, storage, security, operating
systems, and applications, will now be more integrated than the
industry has ever been in the past. You will be concerned with not
only the network but with storage, security, and all the other
systems that must work together in both corporate and cloud data
centers.
Preparing for Life in the Cloud As a student, there is much to
learn to become CCNA Cloud certifi ed. We will cover all the topics
that the CCNA Cloud blueprint outlines and that is specifi c to
Cisco’s intercloud and the family of products that are used, such
as the UCS, the Nexus and MDS products, and the software management
products in the Cisco portfolio. You will also need to learn much
more than networking. Topics such as storage systems, operating
systems, server hardware, and more will require your understanding
and knowledge for you to be a cloud engineer.
The cloud marketplace is growing and changing at a breakneck pace,
and as such, you will need to be constantly learning the new
offerings just to keep up. New services and offerings from the
cloud providers are being released weekly, and existing products
are con- stantly being improved and expanded. The learning will
never stop!
It is important to learn the terms and structure in the cloud that
the CLDFND 210-451 exam covers as a strong knowledge base. From
these topics, you can build and expand your knowledge in more
specifi c and detailed topics in cloud computing. You are advised
to fully understand the big picture of cloud computing and build on
that as you gather knowledge and expertise.
The Evolutionary History of Cloud Computing 7
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Computing
In this section, you will step back and look at how the world of
computing has evolved over the decades. This will help you get some
historical perspective and to see that what was once old can now be
new again! Once you have an understanding of the past, we will give
you a quick look at where we are today and make a few predictions
of where we are headed.
A Brief History of Computing The history of computing is a rather
large topic area, and some of us who have been in the industry for
many years can sometimes be nostalgic of the good ol’ days. At the
same, time we can admit to being shocked when walking through the
Smithsonian museum in Washington, DC, and seeing “historical”
equipment that we used to work on! In IT, it is not an
understatement that the technology and, more specifi cally, the
computing and net- working industry have evolved at a very fast
speed. It is also true that the only constant is change and that
the change is happening at a faster pace than ever before.
Computing in the Past Back in the dark ages of computing, the
computers were large, expensive, and complicated, and they had
limited processing power by today’s standards. In fact, today the
smartphones we carry in our pockets are more powerful than most of
the room-sized computers of the past.
The original architecture of computing was that of large,
centralized systems that were accessed with remote systems with
limited intelligence and computing power. Over the years, the large
mainframes gave way to multiple minicomputers , as shown in Figure
1.2 , which were still housed in climate-controlled computer rooms
with dumb terminals using only a keyboard and monitor to access the
processing capabilities of the minicomputers.
F I GU R E 1. 2 Mainframe and minicomputers
MinicomputersMainframes
When the Intel-based servers entered the marketplace and local area
networks made their fi rst appearance, there was a fundamental
shift in the industry. The power of
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computing moved out from the “big glass rooms” that computer rooms
were called back then and into the departmental areas of the
corporations. This new client-server architec- ture was that of
distributed computing where a central fi le server was used to
store data and offered printing services to a large number of
personal computers; the central fi le server was the replacement of
the dumb terminals used in the mainframe and minicomputer world
(see Figure 1.3 ). This was a huge industry change where the end
users of systems gained control over their computing requirements
and operations.
F I GU R E 1. 3 Client-server computing
Client-server systems were not without their problems, however.
Many islands of com- puting networks sprung up everywhere, and
there were many proprietary protocols that meant most of these
systems were not compatible with each other; hence, there was no
interoperability. Data was now scattered all over the company with
no central control of security, data integrity, or the ability to
manage the company’s valuable data. Networking these client-server
systems across a wide area network was at best expensive and slow
and at worst unattainable.
As the industry grew and evolved, it would frequently revert to
what was old but cleaned up and presented as something new. One
example is how the client-server systems were brought back into the
data center, internetworked, and patched, with management and
redundancy implemented; most importantly, that valuable data was
collected and managed in a central area. Over time that myriad of
proprietary, vendor-developed protocols, shown in Figure 1.4 ,
slowly became obsolete. This was a major development in the
networking industry as TCP/IP (Transmission Control
Protocol/Internet Protocol) became the standard communications
protocol and allowed the many different comput- ing systems to
communicate using a standardized protocol.
During the consolidation era, wide area networking evolved from
slow dial-up lines and either analog or subrate digital telco
circuits that were all leased from the local phone companies for
private use to a now open public network called the Internet with
high-speed fi ber optic networks widely available.
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With the opening of the Internet to the world and the emergence of
the World Wide Web, the world became interconnected, and the
computing industry fl ourished, with the networking industry
exploding right along with it. Now that we have become intercon-
nected, the innovation in applications opened a whole new area of
what computing can offer, all leading up to the cloud computing
models of today.
Computing in the Present Day Corporate-owned data center models
that provide compute and storage resources for the company are
predominate today. These data centers can be either company owned
or leased from a hosting facility where many companies install
equipment in secure data centers owned by a third party. As we
discussed earlier in this chapter, traditional data centers are
designed for peak workload conditions, with the servers being
unused or lightly used dur- ing times of low workloads.
Corporate data centers require a large up-front capital investment
in building facilities, backup power, cooling systems, and
redundant network connections in addition to the racks of servers,
network equipment, and storage systems. Also, because of business
conti- nuity needs, there are usually one or more backup data
centers that can take the workload should the primary data center
go offl ine for any reason.
In addition to the up-front costs, there are ongoing operational
costs such as mainte- nance and support, power and cooling costs, a
large staff of talented engineers to keep it all running, and
usually a large number of programmers working on the applications
that the companies require to operate their business. There are
many other costs such as software licensing that add to the expense
of a company operating its own data centers.
F I GU R E 1. 4 Incompatible communications protocols
Vines
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This is not to say that modern data center operations are not using
much of the same technology as the cloud data centers are using.
They are. Server virtualization has been in use for many years, and
large centralized storage arrays are found in the private data cen-
ters just as they are in the cloud facilities.
With the current marketing hype surrounding cloud computing, many
companies have rebranded their internal data centers to be private
clouds. This is valid because they have exclusive use of the data
center and implement automation and virtualization; many of the
cloud technologies and processes are also found in the corporate
data centers.
The Future of Computing Clearly the future of computing is to move
to the shared model of service offerings of the cloud. This can be
witnessed by the high growth rates of the large cloud providers.
The move to the cloud has been nothing less than a massive paradigm
shift in the industry to public clouds, as shown in Figure 1.5 .
The business case and fi nancial models are too great to ignore.
There is also the ability of cloud services to be implemented very
rapidly and with elastic computing technology that can expand and
contract on the fl y. Companies can save the large capital expenses
of owning and operating their own data centers and focusing on
their core business while outsourcing their computing requirements
to the cloud.
F I GU R E 1.5 Cloud computing model
Public Cloud
Public Cloud
Public Cloud
For smaller companies or startups, the low costs and advanced
service offerings of the cloud companies are too great not to use
cloud services. Also, as is apparent, the time to market or time to
get an operation up and running is very fast with cloud services,
where advanced services can be implemented in hours or a few short
days. Technologies that were available only to large corporations
with massive budgets to apply to information technolo- gies are now
available to the “little guys.”
What Exactly Is Cloud Computing? 11
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The Great Cloud Journey: How We Got Here We are just getting
started with widespread cloud technologies and offerings. The great
migration to cloud computing has just begun, and we have a long way
to go if we look at the recent and projected growth rate of the
cloud service providers.
The nature of the network engineer’s job is clearly going to
change. How much and where it is headed is open for debate. We feel
that the days of silos where each engineering discipline, such as
networking, application support, storage, and the Linux and Windows
teams will all blur together, and we must all become familiar with
technologies outside of our core competencies.
As you can see, what is old is now new again because the ability to
take a piece of technology and virtualize it into many systems on
the same hardware was the great enabler that got us to where we are
today. Along the way, some amazing software was developed to
implement and manage these new clouds. As you will see on your way
to becoming CCNA Cloud certifi ed, Cisco clearly intends to be a
big player in this market and has developed a suite of cloud
software and services to enable not only a single cloud but a group
of clouds, the intercloud , to operate. This is a very exciting
time for our industry!
What Exactly Is Cloud Computing?
What is cloud computing? Well, that can be a bit complicated and
convoluted with all of the marketing hype surrounding this
technology area that has such a high growth rate and the attention
of the world.
A cynic would note that everything in the past has been relabeled
to be “cloud this and cloud that.” Anything that was connected to
the Internet and offered to the public now seems to be called a
cloud service. The cloud marketplace is also very large and growing
at a fast pace. Because of this rapid expansion, there are many
sections and subsections to this new industry. There are many types
of different clouds and services offered. Applications and
technologies that have been in place for many years now have cloud
attached to their name, while at the same time, the development of
new cloud service offerings seems to be a daily event with a
constant stream of new product announcements.
Cloud computing is essentially outsourcing g data center
operations, applications, or a section of operations to a provider
of computing resources often called a cloud company or cloud
service provider. The rr consumer of cloud services pays either a
monthly charge or by the amount of usage of the service. You will
explore many different models and types of cloud computing in this
book.
While there may never be agreement on a clear and concise defi
nition, you can turn to the organization that keeps track of these
things, the National Institute of Standards and Technologies (NIST
), as the authoritative source for what you are looking for.
12 Chapter 1 Fundamentals of Cloud Computing
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The NIST Definition of the Cloud NIST SP 800-145 is the main source
of cloud computing defi nitions. NIST defi nes cloud computing
as:
…a model for enabling convenient, on-demand network access to a d
shared pool of configurable computing resources (e.g., networks,
servers, storage, applications, and services) that can be rapidly
provisioned and released with minimal management effort or service
provider interaction. This cloud model is composed of five
essential characteristics, three service models, and four
deployment models.
That seems to the point and accurate, with no spin and just the
facts. There seems to be agreement that the cloud is an on-demand
self-service computing service and is the most common defi nition.
That is something us as engineers really appreciate. Of course,
behind this defi nition is so much technology it is going to make
your head spin and sometimes overwhelm you, but that’s the
business.
In this book, you will investigate all of the models and
characteristics and then dig into the technologies that make all of
this work. When you are done, you will be proud to call yourself
CCNA Cloud certifi ed!
How Many Definitions Are There? There are many defi nitions of
cloud computing. Some are accurate, and many are just spins on
older, already existing offerings and technologies. It is advised
that you understand the big picture of cloud computing and then dig
into the fi ner details and not get caught up in the excitement
surrounding cloud computing. It is our job to make it work, not to
keep it polished for the whole world to see.
The Many Types of Clouds While the defi nition of the cloud can be
very generic and broad, you can get granular with the different
types of service models and deployment models. These will be
explored in detail in the following two chapters. Service models
break down and defi ne basic cloud offerings in what is provided by
the cloud provider and what you will be responsible for as the
cloud customer.
Service Models For example, there are three main service categories
that are defi ned (and many more that are not in these groups). The
three main service models include Infrastructure as a Service
(IaaS), Platform as a Service (PaaS), and Software as a Service
(SaaS). With Infrastructure as a Service, as shown in Figure 1.6 ,
the cloud provider generally provides all the systems that make up
a data center deployment such as the server platform, storage, and
network but leaves the operating system and application
responsibilities to the customer. This has
What Exactly Is Cloud Computing? 13
c01.indd 03/26/2018 Page 13
been the predominate cloud service model until recently and allows
the customer complete control and responsibility of the operating
system and applications.
F I GU R E 1.6 Infrastructure as a Service
IaaS Storage
Processing Networking
The Platform as a Service model, shown in Figure 1.7 , moves one
step up the stack, and the cloud provider takes on operating system
responsibilities. This is to say that the cloud company owns the
responsibility of loading and maintaining either a Microsoft
Windows operating system variant or one of the many different
releases of Linux. With the Platform as a Service model, the cloud
customer is responsible for the applications running in the cloud,
and the provider takes care of all the underlying infrastructure
and operating systems.
F I GU R E 1.7 Platform as a Service
PaaS Operating Systems
Compute
At the top of the stack is the Software as a Service model, as
shown in Figure 1.8 , which is just like it sounds: The cloud
company provides a complete package including the application that
can be a wide variety of solutions, such as database, enterprise
resource planning, software development applications, or most any
mainstream application that is currently running in corporate data
centers.
14 Chapter 1 Fundamentals of Cloud Computing
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F I GU R E 1. 8 Software as a Service
SaaS
Networking
Cloud deployment models defi ne the larger topic of where the cloud
is deployed and who is responsible for the operations. There are
four main cloud deployment models that include the public cloud,
the private cloud, the community cloud, and fi nally the hybrid
cloud, as illustrated in Figure 1.9 . You will learn the details of
these models in Chapter 3, but you will get an overview in this
chapter.
F I GU R E 1. 9 Cloud deployment models
Public Cloud Private Cloud Community Cloud Hybrid Cloud
The public cloud is probably the most widely deployed and
discussed, as illustrated in Figure 1.10 . The public cloud is
usually what we tend to think of when we hear the term cloud being
tossed around. This includes the cloud companies that make up the
intercloud, d in other words, the major players in the market, such
as Amazon Web Services, Microsoft Azure, and Google Cloud Services,
along with many other companies. The public cloud is where a
company offers cloud computing services to the public in the
utility model covered earlier in the chapter.
The private cloud is predominantly computing services that are
privately owned and operated and are not open to the public.
Corporate data centers fi t into the private cloud defi nition.
Private clouds are owned by a single organization such as a
corporation or a third-party provider (see Figure 1.11 ). Private
clouds can be either on-premises or off-site at a remote hosting
facility with dedicated hardware for the private cloud.
What Exactly Is Cloud Computing? 15
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F I GU R E 1.11 A single organization accessing a private
cloud
Private Cloud
A community cloud, as shown in Figure 1.12 , is designed around a
community of inter- est and shared by companies with similar
requirements. For example, companies in the healthcare or fi
nancial services markets will have similar regulatory requirements
that have to be adhered to. A public cloud offering can be designed
around these requirements and offered to that specifi c marketplace
or industry.
Finally, there is the hybrid cloud model, which is the
interconnection of the various cloud models defi ned earlier, as
illustrated in Figure 1.13 . If a corporation has its own private
cloud but is also connected to the public cloud for additional
services, then that would con- stitute a hybrid cloud. A community
cloud used for specifi c requirements and also connected to the
public cloud for general processing needs would also be considered
a hybrid cloud.
As you will learn, the intercloud technologies from Cisco enable
the hybrid cloud model. This will be investigated in detail in the
second part of this book that covers the Cisco Cloud Administration
(CLDM) 210-455 exam.
F I GU R E 1.10 Multiple organizations sharing a public cloud
service
Public Cloud
Company A
Company B
Company C
Company D
Company E
Company F
c01.indd 03/26/2018 Page 16
Introducing the Data Center
This section will provide an overview of the modern data center and
the business models, deployment models, and support services. The
section will also discuss how to design a data center for the
anticipated workload. Since the topic of data center design and
opera- tions could fi ll many books, we will not attempt to go into
great detail as it is not required for the Understanding Cisco
Cloud Fundamentals exam 210-451. However, it is important to
understand the layout and basic designs of the modern data center,
which is what we will accomplish in this section.
F I GU R E 1.12 The community cloud based on common interests
or requirements
Healthcare Community Cloud
Banking Community Cloud
Legal Community Cloud
Law Office
F I GU R E 1.13 The hybrid is a combination of clouds.
Community Cloud
c01.indd 03/26/2018 Page 17
The Modern Data Center There is a common design structure to the
modern data center, no matter if it is a privately owned data
center, a hosting facility, or a data center that is owned by a
cloud company. They are all data centers, and the structure and
design are common between them all.
We will start by taking a closer look at what their basic
requirements are. Data centers are going to consume a rather large
amount of electrical power and need access to high- speed
communications networks. Since they may contain sensitive or
critical data, both data security and physical security are
requirements. From those fundamental needs, we will look at the
various components of the data center to allow you to have a good
under- standing of all the pieces that come together to make a
fully functioning modern data center.
It is a truism that data centers are real power sinks! The servers,
storage systems, net- work gear, and supporting systems all require
electricity to operate. Most data centers tend to be quite large to
obtain economies of scale that make them more cost effective. This
means that being connected to a power grid that has capacity and
stability is critical. Also, plans must be made for the eventuality
of a power failure. What do you do then? A modern data center can
generate its own power if the main power grid from the local
utility fails. There may also be massive racks of battery or other
stored power systems to power the data center momentarily between
the time the power grid fails and the local data generation sys-
tems come online.
Data must come and go not only inside the systems in the data
center, which is com- monly called east-west traffi c, but also
from the outside world, which is referred to as t north-south data.
This will require the ability to connect to high-speed data
networks. These fi ber networks can be owned and operated by the
same company that owns the data center or, more likely, a service
provider that specializes in networking services. These net- works
tend to be almost exclusively fi ber-optic, and it is preferable to
have more than one entry point into the data center for the fi ber
to avoid a single point of failure. You will also notice that there
will be two or more service providers connected to allow for
network con- nectivity if one of the provider’s networks
experiences problems and there is a need to fail over to the backup
network provider.
With the power and communications addressed, you will fi nd that
data centers are located in secure areas with security gates,
cameras, and guards protecting the physical building and its
grounds.
Inside of the data center you will fi nd distribution systems for
power and communica- tions and an operations center that is tasked
with monitoring and maintaining operations. The fl oor for the data
center will be raised tiles to allow cable trays for the power and
sometimes communications cables to interconnect the racks inside
the computer room.
There will be rows of equipment cabinets to house all of the
servers, storage systems, switches, routers, load balancers, fi
rewalls, monitoring systems, and a host of other hard- ware needed
for operations.
In addition, all of the electronics in the data center generate a
lot of thermal heat. This is not trivial and must be addressed with
large cooling systems, or chillers, as we like to call them, to get
the heat out of the data center to protect the electronics inside
the enclosures.
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While no two data centers seem to be the same, these basic
components are what make up the modern data centers found around
the world.
Business Models Cloud-based business models can be distilled to
four basic models that IT channel companies are adopting. While
there are, of course, a large variety of companies in the cloud
business space, each with their own way of doing business, we will
look at the more common models.
The “build it” model is a natural progression in the IT industry to
help customers build a private cloud. There are also many companies
that have built very large public cloud offerings. The “provide or
provision” category providers can either resell or relabel a ven-
dor’s cloud offering. They can also operate their own data center
and sell homegrown cloud services. Many companies follow the
“manage and support” model, which includes ongoing management and
support of cloud-based services such as remote monitoring and
management and security offerings. With the “enabling or
integration model” solution, providers work with customers in a
professional services role to assist in the business and technical
aspects of their startup and ongoing cloud operations.
Data Center Deployment Models Data center deployment models
encompass subjects such as usable square footage, the den- sity of
server and storage systems, and cooling techniques. In the cloud it
is common to use a regional deployment model and implement multiple
data centers per region into availabil- ity zones.
A cloud service provider will offer regions for customers to
provide their deployments. For example, there may be USA Central,
Brazil, and China East regions that are selected to deploy your
cloud applications. Each region will be segmented into multiple
availabil- ity zones that allow for redundancy. An availability
zone is usually a complete and sepa- rate data center in the same
region. Should one zone fail, cloud providers can fail over to
another availability zone for continuity and to alleviate a loss of
service.
Data Center Operations Data center operations concern the workfl ow
and processes conducted in the data center. This includes both
compute and noncompute operations specifi c to the data center; the
operations include all the processes needed to maintain the data
center.
Infrastructure support includes the ongoing installation, cabling,
maintenance, moni- toring, patching and updating of servers,
storage, and networking systems. Security is an important component
to operations, and there are both physical and logical security
mod- els. Security includes all security processes, tools, and
systems to maintain both physical and logical security. Power and
cooling operations maintain suffi cient power, and cooling is
reliably available in the data center. Of course, there will also
be a management component that includes policy development,
monitoring, and enforcement.
The Difference Between the Data Center and Cloud Computing Models
19
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Designing the Data Center for the Anticipated Workload The data
center must be scaled not only for the present but for the
anticipated workload. This can be tricky as there are many
unknowns. Server technology is constantly evolving, allowing you to
do more processing in less rack space, and the silicon used in the
physical devices has become more power effi cient as well, enabling
more processing per power unit. When designing a data center, items
such as square footage, power, cooling, communica- tions, and
connections all must be considered.
The Difference Between the Data Center
and Cloud Computing Models
In this section, we will contrast and compare what makes the cloud
model different from the traditional corporate computing
model.
The traditional corporate data center utilizes the approach of
purchasing and hav- ing available enough additional computing
capacity to allow for times when there is a peak workload. This is
terribly ineffi cient as it requires a signifi cant up-front
investment in technology that may rarely get used but that needs to
be available during the times it is required. Also, the lead times
from concept to deployment in the data center can take months or
even years to complete.
The differentiation is that, in theory at least, the resources are
always available in the cloud and just sitting there waiting to be
turned on at the click of an icon with your mouse. The cloud
computing model then is that of a utility, as we have discussed.
You order only what you need and pay for only what you use. The
cloud model has many of the advan- tages of traditional data
centers in that there is a huge, and constantly growing, amount of
advanced offerings that would never have been possible to implement
for most small and medium-sized businesses, or even large ones in
some cases. If you are a business located in the United States but
have many customers in Asia, you may want to store your web con-
tent in Japan, for example, to provide for faster response times in
Asia. In a traditional data center model, this would probably not
be practical. With these services offered, your cloud provider may
have access points in many Asian countries with your web content
locally stored for fast response times since the request no longer
has to come all the way to the United States for the data be served
out of the local web server and the content returned to Asia.
Another advanced and costly service that is out of the realm of
possibility for most companies is the cloud feature of availability
zones offered in the cloud; for example, if you as the cloud
provider have a data center go down, you can automatically shift
all of your cloud services to another availability zone, and the
people accessing your site in the cloud may not have even noticed
what happened.
There are many other examples of the differences between the
traditional data center model and the cloud as it is today and as
it continues to evolve. We will explore these differ- ences and
contrast the advantages of cloud computing in this book as we go
along.
20 Chapter 1 Fundamentals of Cloud Computing
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Common Cloud Characteristics
In this section, you will learn about the common characteristics
that make up a cloud computing operation. We will start with the
core principle of the cloud model, which is on- demand computing,
and then move on to discuss the ability to automatically expand and
contract by discussing the concept of elasticity. We will look at
several scaling techniques commonly deployed, including whether to
scale up or scale out. The concept of resource pooling will be
explored with a look at the various types of pools such as CPUs,
memory, storage, and networking.
Metered services will be discussed, and you will learn that with
the ability to measure the consumed services, the cloud company can
offer many different billing options.
Finally, we will end this section by exploring the different
methods commonly utilized to access the cloud remotely.
On-Demand Self-Service The on-demand cloud services allow the
customer to access a self-service portal, usually d with a web
browser or application programmable interface (API), and instantly
create addi- tional servers, storage, processing power, or any
other services as required.
If the computing workload increases, then additional resources can
be created and applied as needed. On-demand allows you to consume
cloud services only as needed and scale back when they are no
longer required. For example, if your e-commerce site is expecting
an increased load during a sales promotion that lasts for several
weeks, on- demand services can be used to provision the additional
resources of the website only during this time frame, and when the
workload goes back to normal, the resources can be removed or
scaled back. You can also refer to on-demand self-service as a
just-in-time service because it allows cloud services to be added
as required and removed based on the workload.
On-demand services are entirely controlled by the cloud customer,
and with cloud auto- mation systems, the request from the customer
will be automatically deployed in a short amount of time.
Elasticity Elasticity provides for on-demand provisioning of
resources in near real time. The ability to add and remove or to
increase and decrease computing resources is called elasticity.
Cloudy resources can be storage, CPUs, memory, and even servers.
When the cloud user’s deploy- ment experiences a shortage of a
resource, the cloud automation systems can automatically and
dynamically add the needed resources.
Elasticity is done “on the fl y” as needed and is different from
provisioning servers with added resources that may be required in
the future. Elasticity allows cloud consumers to automatically
scale up as their workload increases and then have the cloud
automation sys- tems remove the services after the workload
subsides. With cloud management software,
Common Cloud Characteristics 21
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performance and utilization thresholds can be defi ned, and when
these metrics are met, the cloud automation software can
automatically add resources to allow the metrics to remain in a
defi ned range. When the workload subsides, the service that was
added will be auto- matically removed or scaled back.
With elastic computing, there is no longer any need to deploy
servers and storage sys- tems designed to handle peak loads—servers
and systems that may otherwise sit idle during normal operations.
Now you can scale the cloud infrastructure to what is the normal
load and automatically expand as needed when the occasion
arises.
Scaling Up When additional computing capacity is needed in the
cloud, the scaling up approach is one in which larger and more
power servers are used to replace a smaller system, as shown in
Figure 1.14 . Instead of adding more and additional servers, for
example, the scale-up model will instead replace the smaller with
the larger.
F I GU R E 1.14 Scaling up increases the capacity of a
server.
Cloud Server Upgraded
Vertical scaling increases the capacity of an existing
server.
You will learn throughout this book that there is a lot more to
cloud capacity than just raw compute power. For example, a system
may have more than enough CPU capacity but instead need additional
storage read/write bandwidth if it is running a database that needs
constant access with fast response times. Another example of
scaling up would be a web server that sends large graphics fi les
to remote connections and is constantly saturating its LAN
bandwidth and necessitating the need to add more network I/O
bandwidth.
Cloud service providers offer many options when selecting services
to meet your require- ments, and they offer multiple tiers of
capacity to allow for growth. For example, there are many different
server virtual machine options available in the cloud that offer
scalable com- pute power, with others designed for different
storage applications, graphics processing, and network I/O.
Scaling Out Scaling out is the second, and arguably more common,
approach to additional capacity in t the cloud, as shown in Figure
1.15 . The scaling-out design utilizes additional resources that
are incrementally added to your existing cloud operations instead
of replacing them with a larger and more powerful system.
22 Chapter 1 Fundamentals of Cloud Computing
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F I GU R E 1.15 Scaling out by adding additional servers to
accommodate
increased workloads
Cloud Servers
Load Balancer
Scaling out adds more servers for additional capacity.
For example, if the cloud web servers are experiencing a heavy load
and the CPU utiliza- tion exceeds a predefi ned threshold of say,
85 percent, additional web servers can be added to the existing web
servers to share the workload. The use of multiple web servers
servicing the same web domain is accomplished with the use of load
balancers that spread the con- nections across multiple web
servers.
Cloud Elasticity Use Cases There are many examples where elasticity
can be a valuable cloud feature to implement to save money and
maintain performance levels. It is desirable to design the cloud
computing resources for your anticipated day-to-day needs and then
to add resources as required. A company that needs to process data
for business intelligence will often have a large process- ing job
that would take a very long time to run on available servers that
would then sit idle until the process repeats. In this case, many
servers, sometimes in the hundreds, can be pro- visioned for the
job to run in a timely manner, and when complete, the servers are
removed, and the company will no longer be charged for their
use.
Many e-commerce retailers experience heavy traffi c during the
holiday season and then see their web traffi c drop signifi cantly
for the rest of the year. It makes no sense to pay for the needed
web capacity over the holiday season for the rest of the year. This
is a prime use case for the value of cloud elasticity. As you are
probably noticing, you can either scale up or scale out, and the
provisioning can be done automatically or manually through the web
confi guration portal and using automation.
Resource Pooling Resource pooling is the term used to defi ne when
the cloud service provider allocates g resources into a group, or
pool , and then these pools are made available to a multitenant l
cloud environment.
The resources that are pooled are then dynamically allocated and
reallocated as the demand requires. Resource pooling takes
advantage of virtualization technologies to abstract what used to
be physical systems into virtual allocations or pools.
Resource
Common Cloud Characteristics 23
c01.indd 03/26/2018 Page 23
pooling hides the physical hardware from the virtual machines and
allows for many tenants to share the available resources, as shown
in Figure 1.16 .
F I GU R E 1.16 Resource pooling
Storage NetworkMemory Compute
Hypervisor
A physical server may have 256 CPU cores and 1,204GB of RAM on the
motherboard. The CPU and memory can be broken into pools, and these
pools can be allocated to indi- vidual groups that are running
virtual machines on the server. If a virtual machine needs more
memory or CPU resources, with scaling and elasticity, these can be
accessed from the pool. Since processing power, storage, network
bandwidth, and storage are fi nite resources, the use of pooling
will allow for their more effi cient use since they are now being
shared in a pool for multiple users to access as required.
CPU A physical nonvirtualized server running a single operating
system uses the processing power of the CPUs installed on its
motherboard.
In the case of a virtualized server, it will have tens or even
hundreds of virtual machines all operating on the same server at
the same time. The virtualization software’s job is to allocate the
physical or hard resources on the motherboard to the virtual
machines running on it. The hypervisor virtualizes the physical
CPUs into virtual CPUs , and then the VMs running on the hypervisor
will be allocated these virtual CPUs for processing. By using
virtualized CPUs, VMs can be assigned or allocated CPUs for use
that are not physical but rather virtual. The virtualization
function is the role of the hypervisor. Pools of CPUs can be
created using administrative controls, and these pools are used or
consumed by the virtual machines. When a VM is created, resources
will be defi ned that will determine how much CPU, RAM, storage,
and LAN capacity it will consume. These allocations can be
dynamically expanded up to the hard quota limits based on the cloud
provider’s offerings.
Memory Memory virtualization and its allocations to the virtual
machines use the same concepts that we discussed in the previous
section on virtualizing CPUs. There is a total and fi nite amount
of RAM installed in a bare-metal or physical server. This RAM is
then virtualized
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by the hypervisor software and allocated to the virtual machines.
As with the allocation of processing resources, you can assign a
base amount of RAM per virtual machine and dynamically increase the
memory available to the VM based on the needs and limits confi g-
ured for the virtual machine.
When the VM’s operating system consumes all the available memory,
it will begin to utilize storage for its operations. This swap fi
le , as it is called, will be used in place of RAM for its
operation and is undesirable as it results in poor performance.
When confi guring a VM, it is important to consider that storage
space must be allocated for the swap fi le and that the storage
latency of the swap fi le will have a negative impact on the
performance of the server.
Storage We will cover storage systems in great detail in later
chapters; however, to better under- stand cloud operations, we will
explore storage allocations in the cloud here to gain a more
complete understanding of basic cloud operations.
Storage systems are usually separate systems from the actual
physical servers in the cloud and in private data centers. These
are large storage arrays of disks and controllers that are accessed
by the servers over dedicated storage communication networks. As
you can imagine, these storage arrays are massive and can store
petabytes of data on each sys- tem, and there can be tens or even
hundreds of these systems in a large data center.
Each physical server will usually not have very many disk drives
installed in it for use by the VMs running on that server. Often
cloud servers will contain no hard drives at all, and storage will
be accessed remotely.
With these large storage systems being external from the servers
and connected over a storage area network, the design of the SAN
and storage arrays is critical for server and application
performance. The systems must be engineered to avoid high read and
write latency on the drives or contention over the storage network,
for optimal performance.
To alleviate performance issues, cloud providers use
enterprise-grade storage systems with high disk RPM rates, fast
I/O, suffi cient bandwidth to the storage controller, and SAN
controller interfaces that are fast enough to handle the storage
traffi c load across the network. Cloud service providers will
offer a wide variety of storage options to meet the requirements of
the applications. There can be fast permanent storage all the way
to offl ine backup storage that can take hours or days to retrieve.
Storage allocations can also be used temporarily and then deleted
when the virtual machine is powered off. By using a multi- tiered
storage model, the cloud providers offer storage services priced
for the needs of their customers.
One major advantage of designing the cloud storage arrays to be
remote from the virtual machines they support is that this allows
the cloud management applications to move the VMs from one
hypervisor to another both inside a cloud data center or even
between data centers. The VM will move and continue to access its
storage over the storage network. This can even be accomplished
where an application will continue to operate even as it is being
moved between physical servers. Centralized storage is an enabler
of this technology and is useful for maintenance, cloud bursting,
fault tolerance, and disaster recovery purposes.
Common Cloud Characteristics 25
c01.indd 03/26/2018 Page 25
As with the CPUs discussed in the previous section, storage systems
are allocated into virtual pools, and then the pools are allocated
for dynamic use by the virtual machines.
Networking Networking services can be virtualized like CPU cores
and storage facilities are. Networking is virtualized in many
different aspects, as the Understanding Cisco Cloud Fundamentals
exam covers extensively. In this section, we will briefl y discuss
the virtualization of LAN network interface cards and switches in
servers. NICs and switchports are virtualized and then allocated to
virtual machines.
A typical server in the cloud data center will be connected to an
external physical LAN switch with multiple high-speed Ethernet LAN
interfaces. These interfaces are grouped together or aggregated
into channel groups for additional throughput and fault tolerance.
LAN interfaces in the server are connected to a virtual switch
running as a software appli- cation on the hypervisor. Each VM will
have one or more connections to this virtual switch using its
virtual NIC (vNIC). The LAN bandwidth and capacity is then
allocated to each VM as was done with processing, memory, and
storage discussed earlier. By using multiple physical NICs
connecting to multiple external switches, the network can be
designed to offer a highly fault-tolerant operation. However, since
the available amount of LAN band- width is a fi nite resource just
like the other resources on the server, it will be shared with all
VMs running on the server.
Metered Service A cloud provider will meter, or measure, the usage
of cloud resources with its network monitoring systems. Metering
collects the usage data, which is valuable to track system uti-
lization for future growth, and the data allows us to know when to
use elasticity to add or remove and to scale up or scale down
resources in the day-to-day operation of the cloud.
This metered service data is also used for billing and reporting
systems that can be viewed in the cloud management portal, or
dashboard as it is commonly called.
Metering is frequently used to measure resource usage for billing
purposes. Examples are the amount of Internet bandwidth consumed,
storage traffi c over the SAN, gigabytes of storage consumed, the
number of DNS queries received over a period of time, or database
queries consumed.
There are many examples and use cases for metering services in the
cloud. Many cloud services can be purchased to run for a fi xed
amount of time; for example, batch jobs can be run overnight and
with metered systems, and VMs can be brought online to run these
jobs at a certain time and then shut down when the job is
completed.
Cloud Access Options Connections to the cloud provider are
generally over the Internet. Since cloud data centers are at remote
locations from the users accessing the services, there are multiple
methods used to connect to the cloud.
26 Chapter 1 Fundamentals of Cloud Computing
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The most common method is to use a secure, encrypted connection
over the public Internet. Web browsers can use SSL/TLS connections
over TCP port 443, which is com- monly known as an HTTPS
connection. This allows a web browser to access the cloud ser-
vices securely from any remote location that has an Internet
connection.
If the cloud customer needs to connect many users from a company
offi ce or its own data center, a VPN connection is commonly
implemented from a router or a fi rewall to the cloud, and it
offers network-to-network connectivity over the encrypted VPN
tunnel.
For high-bandwidth requirements, the solution is to connect to an
interexchange pro- vider that hosts direct high-speed network
connections from the cloud to the exchange provider. The customer
can also install a high-speed connection from their facility to the
interexchange provider . At the exchange data center, a direct
interconnection between the rr cloud provider and the corporate
network is made. The direct connect model also supports cloud
options such as cloud bursting and hybrid cloud designs where the
corporate cloud and public cloud provider’s data centers are
directly connected.
Exploring the Cloud Multitenancy Model
The ability to take a software package and, by using segmentation,
share it to serve mul- tiple tenants or customers is called
multitenancy. y
Multitenancy is a cost-effective approach when the costs of the
application, its licenses, and its ongoing support agreements are
shared among multiple customers accessing the application hosted in
the cloud.
In a multitenant application deployment, a dedicated share of the
application is allocated to each customer, and the data is kept
private from the other companies accessing the same application.
The multi-instance model is a similar approach, with the difference
being that each consumer has exclusive access to an instance of the
application instead of one single application being shared.
Summary
In this introductory chapter, we explored the history and evolution
of computing, from the early days of computing to where we are
today and where the industry is headed in the future. We then
explored how cloud computing is different from the traditional
models with the evolution to the utility model found in cloud
computing. Virtualization was intro- duced, and you learned about
the role it plays in the cloud.
You then explored the many defi nitions of cloud computing, cloud
growth, how to migrate operations from traditional data centers to
the cloud, and how the role of the CCNA Cloud engineer will fi t
into working with the cloud models. The basic cloud models of
public, private, hybrid, and community were each introduced and
discussed.
Written Lab 27
c01.indd 03/26/2018 Page 27
We then introduced data center business, deployment, and
operational models. How to design a data center for anticipated
workload was then discussed.
This chapter concluded with a look at the common cloud
characteristics, such as on- demand, elasticity, scaling, and
pooling. These characteristics are important base concepts that
will allow you to have a foundation for further discussions in
future chapters.
Keep the concepts covered in this chapter in mind. They provide a
structure that you will build on as you progress on your journey to
becoming a CCNA Cloud certifi ed professional.
Exam Essentials
Understand the basic terms and concepts of cloud computing service
models. Study the service models of IaaS, PaaS, and SaaS, and
understand their differences and what each model includes and
excludes.
Understand the basic concepts of virtualization. Know what
virtualization is and how it is a key enabler of cloud computing.
We will cover this in greater detail in later chapters.
Know the primary cloud deployment models. You will also be expected
to identify what Public, Private, Community, and Hybrid clouds are;
the differences between them; and where they are best used.
Understand the concepts of resource pooling. Be able to identify
the pooled resources in a virtualized cloud that include CPU,
memory, storage, and networking. This topic will be covered in
greater detail in later chapters.
Identify elasticity and scaling terminology and concepts. Cloud
elasticity is the ability to add and remove resources dynamically
in the cloud. Closely related to elasticity is scaling, where you
can scale up your computed resources by moving to a larger server
or scale out by adding additional servers.
Written Lab
Fill in the blanks for the questions provided in the written lab.
You can fi nd the answers to the written labs in Appendix B.
1. Name the three NIST service models of cloud computing.
1.
2.
3.
c01.indd 03/26/2018 Page 28
1.
2.
3.
4.
3. provides for on-demand provisioning of resources in near real
time.
4. is when a cloud provider allocates resources into a group and
makes these available to a multitenant environment.
5. The ability to take a software package and, by using
segmentation, share it to serve multiple tenants or customers is
called .
Review Questions 29
Review Questions
The following questions are designed to test your understanding of
this chapter’s material. You can fi nd the answers to the questions
in Appendix A. For more information on how to obtain additional
questions, please see this book’s Introduction.
1. What model of computing allows for on-demand access without the
need to provide inter- nal systems and purchase technology
hardware?
A. Interexchange
B. Community
C. On-demand
D. Utility
2. When elastic cloud services are required, what model implements
larger, more powerful systems in place of smaller virtual
machines?
A. Elasticity
3. Hypervisors and virtual machines implement what networking
technologies in software? (Choose two.)
A. VPN
B. Switches
C. SAN
D. NICs
4. What virtualization technology allocates pools of memory, CPUs,
and storage to virtual machines?
A. Scaling
B. SAN
C. Hypervisors
D. Orchestration
A. Shared application software
c01.indd 03/26/2018 Page 30
6. What is the ability to segment a software application to serve
multiple tenants called?
A. Scale up
B. Hybrid cloud
C. Multitenancy
D. Elasticity
7. A cloud data center must be designed with what in mind?
A. Workload
B. Interexchanges
C. Virtualization
D. SAN
8. Memory pooling allows for the dynamic allocation of what
resource?
A. Storage
C. RAM
D. SAN
9. Which of the following are considered valid cloud deployment
models? (Choose three.)
A. Public
C. Hybrid
D. Interexchange
E. Resilient
F. Private
10. The public cloud provides which of the following? (Choose
three.)
A. Measured usage
B. Tiered service
C. Exclusive access
11. Which terms are NIST-defined cloud service models? (Choose
three.)
A. Software as a Service
B. Security as a Service
C. Platform as a Service
D. Applications as a Service
E. Communications as a Service
F. Infrastructure as a Service
Review Questions 31
c01.indd 03/26/2018 Page 31
12. What three characteristics are common to the cloud? (Choose
three.)
A. Interconnectivity
E. Resource pooling
F. Ubiquitous access
13. When additional cloud capacity is required, what model adds
virtual machines?
A. Elasticity
D. Scale up
14. Storage systems are interconnected to the virtual servers on
the cloud using what communi- cations technology?
A. LAN
B. SAN
D. VPN
15. Tipofthehat.com is an e-commerce company that hosts its
applications in its private cloud. However, during the busy holiday
season, because of increased workload, it utilizes external cloud
computing capacity to meet demand. What cloud deployment model is
Tipfofthehat.com using?
A. Public
C. Hybrid
D. Multitenant
E. Private
16. What are critical facilities of a modern data center? (Choose
all that apply.)
A. Power
B. Servers
c01.indd 03/26/2018 Page 32
17. What is an example of a private dedicated connection to the
cloud?
A. Interexchange providers
D. SAN
18. What technology was instrumental in the advent of cloud
computing?
A. Mainframes
B. Elasticity
C. Virtualization
D. Scaling
A. Public
B. Corporate
C. Hybrid
D. Community
E. Private
20. Cloud service providers offer high availability by using what
two data center deployments? (Choose two.)
A. Regions